


Ready for the Responsibility?

by danvssomethingorother



Category: Undertale (Video Game)
Genre: (I just want Frisk to remain the silent semi protagonist later on), Deaf Frisk, F/F, F/M, Found Family, Gen, Gender-Neutral Frisk, Goat Mom Is Best Mom, I am late to this fandom, I just want toriel and Sans to be Frisk's parents, Multi, Slow Burn, and Papyrus to be number one uncle, and papa Sans, but better late then never?, little tiny baby Frisk, on hiatus but NOT abandoned, this fic starts with a baby being thrown in the trash but I promise it gets better from there, toriel and Sans don't get together like right away
Language: English
Status: In-Progress
Published: 2018-01-25
Updated: 2018-04-15
Packaged: 2019-03-09 12:19:55
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 4
Words: 10,859
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13481355
Author URL: https://archiveofourown.org/users/danvssomethingorother/pseuds/danvssomethingorother
Summary: Sans finds a baby…a baby human and must choose what to do from here.





	1. Prologue

This wasn’t one of his usual hiding spots, but it would do for now. It was an old bridge, it didn’t really lead anywhere important and there were easier (and safer) ways to get around it but its lack of use made it the perfect spot to hide from Undyne who had become over bearing since she had been promoted to the head of the royal guards.

He knew the kid meant well and she only wanted to prove something but she was driving him up the wall (pretty literally yesterday after her spear was thrown at his head after one too many puns) with her demands he step up his game as a sentry.

He had cheekily, more then once, stepped on top of his sentry station at the demand and more then once sent running from a spear to the head, only being saved by his short cuts.

He sat, closing his eyes and happily taking in the silence and peace around him, legs hanging off the bridge and laying back, fully ready to nap.

Sans’ eyes shot open as one of his slippers slipped off his foot. He would normally laugh at this but it fell fast, away from his fingers trying desperately to grab it, a few seconds too late. It was a slippery shoe, ok he did laugh at that one as he took one of his short cuts down to the bottom of the ravine, not ready to let his favorite shoe slip away.

He smiled imagining his brother’s scowl at him making bad jokes now of all times while he had to wade through the garbage infested water, keeping an eye out for his shoe.

He had tucked his remaining slipper in his jacket pocket seeing no sense in two soggy slippers.

He grumbled loudly as he pushed large heaps of trash aside to get through, humans were frankly disgusting the way they just tossed their garbage where ever they wanted. The lakes and rivers that drained into their water supplies unfortunately ran through some human garbage dumping grounds according to the royal scientists newest findings and it just lead to this. Monsters having to clean up their messes to have access to water, it was depressing and made Sans hate humans more.

Lazily, he shoved another box aside but paused hearing something crying in it. He shoved it closer to the bank and tilted his head hearing the faint, little sobs coming from it.

“Napstablook?” he ventured a guess, he had witnessed the ghost squeeze themselves into the oddest of places just to have a cry.

The crying continued and Sans realized with a jolt that was an infant, too raspy and high pitched to the ghost’s wails.

He popped the box open and found it stacked high with little baby cloths, he stared at the stack in mute horror. He instantly shook his head and prompted himself back into action hearing the raspy little cries under it all, he pulled back the colorful floral pattern baby blanket and once more felt himself staring stupidly down into the box.

He knew right away the tiny, sickly looking child was not a monster. It was human. A human threw away their baby. Slowly he picked the child up and stared at them then turning his disgust away from the child who began to settle down in his arms, little tiny fist weakly brushing curiously against his face.

They threw their child away…like they threw away the garbage around him. He looked towards a broken down engine that had washed its way down here, someone threw their child out like they were broken and useless. As if they had no value.

Sans couldn’t properly describe the disgust he was feeling as he began to inspect the baby closer. They were tiny, malnourished and he was sure if he could smell, they would smell like death seeing the specs of vomit on their cloths and how heavy their diaper was under his hand.

There was a note pinned to them and Sans opened it up to get a better idea at what kind of human would do this to their own child.

He crumpled the note and threw it with the rest of the garbage in rage after reading the single sentence and starred with pity down at the child.

They had stopped crying, Sans merely holding them had calmed them and they began to doze off in the crook of his arm. Sighing he brushed a finger across their sweaty forehead.

“Hey buddy…” he said with a forced smile sinking down on the side of the bank. The baby didn’t respond but began to whimper. Sans shrugged his jacket off and gently wrapped them into it to help keep some of the chill off.

He felt nothing but bones under the jumper they were wearing, while that would have been just fine for a baby skeleton, he doubted it was fine for a baby human.

He glanced into the box, seeing the baby cloths he scattered around, he noticed they all had tags on them. To keep his mind off things he read it out loud.

“Frisk Mart,” he grumbled, he knew that name, most of the garbage tossed down here came from that mart, it must have been quite popular.

The baby brought him out of his scattered thoughts as they began patting his chest.

“Feeling Frisky?” he quipped making them smile continuing to pat his chest with their fist and becoming fussy as they got no food from the skeleton. 

“Don’t start gettin’ fussy, stay frisky,” he chided standing up once more, not entirely sure what he was going to do but knew they were going to die if he didn’t act soon. 

“Hold on tight, I know a short cut,” he mumbled playfully to the child with a wink making them settle in his arms again as his attention shifted to them. He picked up the box and holding it lazily against his side and nestled the child closer to his chest as he disappeared.

As Sans disappeared, his missing shoe washed up onto the shore where he had been standing seconds before, a crumpled up note washed up next to it soon after.

Much later a very confused Napstablook would come across both but would be too depressed to return the shoe to Sans after reading the message on the note that would bring his spirits down again.

It’s too much hassle… I’m not ready for the responsibility. I can’t. I’m sorry.


	2. The Promise

Being a sentry was an unflattering, boring job but compared to where he had come from, Sans felt it was heaven. Sitting out in the middle of the woods, away from everyone for hours at a time could feel isolating and maybe even give too much leeway to have Sans trapped with his thoughts but that was nothing a word search and a good nap couldn’t fix.

That day had been no different from the rest, he sat there for three hours, finishing his puzzle at record speed he didn’t know he was capable of without his morning coffee.

That’s what he got for bringing the word scrambler instead of the crossword, he berated himself kicking his legs up on his post staring off into nothing.

No one came this far and no one really had reason to, ahead of him was nothing but woods that stretched for a few miles. So there was no one to joke with and nothing to help take his minds off of his previous career choice that had costed him his father and his sleep last night. 

The silence had been getting to him, so he decided to just go for a quick walk to clear his mind.

He wasn’t surprised to find a door this deep into the woods, everyone knew about the door to the ruins. It was once the capital of the Underground but long before Sans was born, it was moved to its current position. Only the King and former Queen and maybe a ghost or two knew what was behind that door, it was rumored the Queen spent her time hiding out here and really Sans believed it. Only boss monsters were powerful enough to open the door after all. Sans felt that if he tried hard enough, he could bust it open, but he never really cared to try.

Instead of messing with that, he rapt his fist against the door, not surprised by the lack of response.

“Who’s there?” he answered himself in a mockingly high-pitched voice.

“Harry,” he responded in his usual casual tone.

“Harry Who?!” he practically shrieked in that high-pitched tone, already smiling at the stupidity of this all.

“Harry up and open the door, its freezing out here!” he called out in mock annoyance, playfully waving his fist for good measure before bursting out into laughter at his own stupid joke. 

\---

Over the course of the next few days, he came back time and time again just to get away from his post when the silence and isolation became unbearable. Maybe this wasn’t the best way to spend his time, but it made him feel less empty inside doing something so silly and light hearted.

He didn’t feel like going back to his post, he didn’t want to feel that pain seeping into his bones once more thinking of the past he couldn’t change, so he once more rapt on the door and he did so again and again and again, ten jokes later feeling like he was in his A game.

He was sweating, ribs tickled raw from his laughter, but he just wanted to stay here and keep this up, just a little while longer. 

He glanced at his phone and realized he needed to get home, Pap would be home soon, and his little brother was too young to stay home alone. He needed him home, so he didn’t burn the house down or over exert himself trying to make the house literally spotless. 

He positioned his fist for one last joke, just one to help him keep his smile when Pap got home from school. To keep it bright while helping him with his homework, he wanted Pap to be happy, he was too young to worry about him.

He rapt softer then before for his farewell joke before heading home, he realized he hadn’t gotten any work done today but if a human was gonna appear, it would be from behind this door, so technically he was still at work he reasoned.

If he had skin, he would have jumped out of it when someone answered his knock.

“Who’s there?” a voice, a woman’s voice trying to suppress giggles called back to him.

Sans glanced behind him, trying to determine if this was a sick joke or not but then took a deep breath, put his anxiety away and played along for one last joke, determined to get to the bottom of this later.

“Iva.”

“Iva who?” the giggling woman inquired amused with his joke putting him a little at ease that he was dealing with someone with a great sense of humor.

“Iva sore hand from knocking!”

He laughed along with his mystery jokester, if they liked knock knock jokes, they couldn’t be all bad he supposed. He found even children got annoyed by them after awhile, so it was nice to find someone willing to play along.

\---

Two years passed by and it had become routine. Go to his post, solve his word search, go to Grillby’s, and then wait until just the right time and then head for the door (maybe a nap or two between). She was always there, right on time, an hour before he needed to be home to greet Pap.

He didn’t know her name (though he had a hunch on who it was), but he had never been more at ease talking to a person that wasn’t his kid brother in his entire life. There were no expectations to fail with her, she was just his friend who loved puns and knock knock jokes a little too much like he did.

He rapt at the door as usual, joke already at the edge of his tongue, he was proud of this one.

“Is that you? My puny friend?” the woman asked almost nervously, unlike her usual confident tone. 

“I think your line was ‘who’s there?’” he said with a frown, his friend was acting strange, “Something got your goat?”

She chuckled at that but didn’t respond right away, she must have prepared a speech of some kind, pressing his skull against the door he could hear the crinkling of paper. 

“We talk everyday, yet I feel like we barely know each other, and I wanted to know you more. Not just your jokes, I want to just talk to someone else who understands.” 

“I think we know each other plenty,” Sans argued leaning against the door shrugging his shoulders, “Jokes reveal more about a person then you realize.”

“You have a bit of a thing for goat puns, so you must be a goat monster, you are patient even when I’m not making sense and even help correct my word play when my tongue is in knots, so must want to be a teacher and you have that kind of voice and tone that just screams mom of the year. Am I missing anything?”

And you’re are hiding out in the ruins so you must be Asgore’s ex-wife, Sans thought to himself, smile widening. He had heard a lot about Queen Toriel from both his father and the king himself and if this woman wasn’t her, that would be a warm day in Snowdin. Sans felt in strongly in his bones, he couldn’t be wrong about this one.

“You are very perceptive, my friend.” 

“Snow big deal,” Sans shrugged crunching a snow poof with his slipper, “Its my job to be. I am one of the main sentries and Asgore himself has been goating me for ages to become the next royal judge but I’m not that driven. This is just something I do to get by and keep my brother comfortable, not something I want to take seriously.” 

“Your brother…he’s a child?” she asked slowly

“Yeah, he’s taller then me by a few inches now and is really proud,” Sans chuckled, “By next year he will be a foot taller then me, I know it.”

“Are your parents….?”

“Gone,” Sans said looking away, “Have been for awhile. Pap is my only family.”

“I’m so sorry…” she paused taking another breath and he laughed knowing what she wanted.

“Sans, you could say I am a rather Sansational Skeleton.” 

“I could have surmised that from all the bone puns,” she chuckled softly.

Sans smiled before giving her a farewell hearing one of the dogs howling his name in the trees.

\---

It almost felt like Sans finally had a real friend who could understand as the days went by and he talked to the older woman about everything in his life.

Mainly about Papyrus but he let a thing or two slip in about what had happened before he had moved to Snowdin a few years back. Hotland held too many bad memories and he just needed a fresh start for him and his brother. She understood and gave him nothing but sympathy, even offering to make him a pie.

She really was something else.

That didn’t mean he wanted to get too serious though, he liked what they had going, he liked being able to just tell her every bad joke he knew and he loved the fact that she genuinely enjoyed his terrible sense of humor.

Then one day she got very serious again and Sans knew it was bad.

“Sans, what do you know about humans?” she asked before he could even finish his next knock knock joke.

“They have a lot of garbage,” he shrugged not really wanting to discuss humans, humans were the last things he ever wanted to think about again.

“What is your opinion on the king’s laws, his laws of killing any human who steps foot down here.”

“Lady…” Sans groaned desperately, he didn’t want to do this, he knew where this was going. If his suspicions were right and he was talking to the ex queen, he knew her love of children. Even human children, even after what had happened to her own. 

“Please, what do you think of humans?” she was desperate, something must have her goat today and she wasn’t going to stop.

“I think they deserve to die after all they took from us,” he responded looking away.

“Even the children?” she said firmly, “Because those are the only humans who ever end up here. It is only children Sans. Precious little lives who fall down here, alone and afraid.”

“A human is a human,” Sans said firmly, but stopped not wanting to think about this, not wanting to talk about this.

All he could think of was his father telling him it would only be a little while longer and hearing crying. His mother snarling they were no better then humans before she slammed the door shut, never returning leaving Pap screaming for her all through the night.

“Sans, please…listen to me…I can’t protect them…I keep losing them, he keeps killing them,” she was on the verge of crying and it was killing him. He didn’t want to talk about this.

“Please Sans, they are children, hear me out,” he could hear the unsaid ‘I can’t lose another one, Sans’ on the edge of her cracked voice. She must be caught up in the past today.

“They kill the same as the adults,” he mumbled looking off, “They have hate in their heart just the same as the adults do.”

“They are children!” She snarled at him, “They were afraid and they only wished to go home, Sans. You must understand that. You must understand the humans who fall here are always children, afraid and lonely and only wishing to go home.”

“That’s what we want too though and the only way we can escape is with their souls. Children or not, there isn’t anything I can do about it lady, just drop it. I don’t want to think about the humans and I don’t think you should either. There isn’t anything we could do about it anyway.”

“How can you talk like that?!” she yelled making Sans cringe, “What if it was Pap---”

“Don’t you bring my brother into this, he has nothing to do with humans,” Sans snarled his eye already glowing, “I would never let him out of my sight, I’m not irresponsible like the worthless humans who lose their kids here!”

“That’s the thing though Sans,” she said sighing, “ I don’t think they were lost. I think they were all thrown down here, thrown away to die.”

Sans said nothing, he had always had his suspicions but never wanted to go deeper into the subject. He didn’t want to think about this, why was she doing this to him?

“I have seen them go from my door, one by one and each one has died. You told me he now has six souls, each one of those souls was a child who came from here. A child who begged me to let them cross this door, telling me they can do better this time and when they get home their families would be happy they were home. The injuries on their bodies always told a different story.”

“Why are you telling me this lady?” he begged, looking away hoping she would stop already.

“I have been trying to gain courage for a long time, Sans,” she said slowly, “I have been wanting to ask you for so long and after getting to know you better and knowing you are a good person, I am begging you, please promise me to protect the children who cross this door.”

“No,” he said breathing hard and then repeating himself louder and firmer.

“I am not endangering my brother to ease your conscience, if you want them safe, keep them in the ruins.”

“That isn’t always a choice I have---”

“No, I am not going out of my way for humans, I can’t risk it, you know I can’t risk it,” he was breathing hard now. He needed to leave.

“Please…Sans…” she was crying, Sans turned his head away. Oh god, she was crying. She was begging him to say yes to her idiotic promise and expected him to actually commit treason if the time came for it. 

He didn’t answer her, he just left. He went back to his post and didn’t come back to the door for days that slowly bled into two weeks. 

His routine went back to normal before the door became a part of it. He stayed at his post, he went to Grillby’s, he went home. The only difference was her words wouldn’t leave his head. Only children fall into the underground, never adults. Only the ones who were unwanted and unloved. 

That wasn’t entirely true though, he thought one day staring at the wall in Grillby’s, slowly rotating his bar chair and blocking out the world around him. He knew without a doubt there had been one, the one his father had tested the determination extractor on. A teenager who had been the same age as him, the one who tore to the capital, taking down any monster who stood in front of him, yelling for his baby sibling back. 

Sans remembered standing behind his father in the judgement hall, his father taking this duty after the boy had killed the official judge. His father, no nonsense as ever telling him his sibling had already died by the king’s hands.

Sans had expected a fight, he had cowardly backed away ready to teleport if the boy got violent but he hadn’t. He sort of … deflated after the news, muttering there was no point going on then…his sibling was all he had.

The great Dr. W.D. Gaster had actually comforted him as he cried before putting him through a fait worse then death before he harvested his soul.

Sans didn’t finish his fries, he left them there and called for Grillby to put it on his tab. Maybe that boy deserved to die, he had killed a few people but he didn’t know about his sibling, they might not have done anything to deserve death. They must have been small, maybe Pap’s age. 

His sibling was loved and wanted, his older brother came for him, like he would have for Pap and died just as his sibling before him had.

He walked to the door only thinking about Pap alone in the human world without him and considered what awful things he too would have done to get him back unharmed. He shook the thought away of baby brother dying, he couldn’t think of that.

He would want someone to protect Pap until he could find him and maybe protecting a kid was only strategical. It would prevent deaths from the mourning older siblings hell bent on getting them back.

He rapt hard at the door and waited until a shaky ‘Who’s there?’ answered him.

“Someone who is ready to promise to not hurt a human child but if its an adult, they are on their own.”

“I think that is fair,” the woman answered, “It is the children I truly worry for. It is only children who end up here, Sans.”

Sans knew why, humans were disgusting. Treating their home like a dump, tossing down all their unwanted things. Which included children and maybe Sans could relate.

\---

In the present, Sans was exhausted and nervously pacing his lab glancing back at the box he had left the baby in every few seconds. He was worried about the fact they weren’t crying anymore. He didn’t want to drop a surprise like this on Papyrus, so he left them down here, in his lab, the only place he knew for certain Pap wouldn’t find himself in. It was far enough from the house that hopefully his bro wouldn’t be woken up in the middle of the night by the baby either.

Maybe he was wrong, but he liked to keep sensitive subjects like death away from Pap. He didn’t want to introduce his brother to this child until he knew it would live and if it didn’t, well it would remain another skeleton in his own closet.

God he hoped not literally….that would be a visual pun even he didn’t want in his personal space.

Sans took a deep breath and collapsed at his desk and peering inside the laundry basket he had temporarily made into a cradle. 

Frisk, as he had been calling the baby, was sleeping soundly, not too bothered by the fact the best Sans could do for now was stack a few towels and sheets together as a makeshift mattress and messily swaddled them in a blanket he hoped Pap wouldn’t miss from his pile of emergency blankets.

He ran his finger over their burning forehead and smiled as they began to grumpily moan at him, not wanting to be bothered. They began to cry again after being rudely awoken but not nearly as loud as they had been crying. Sans picked them up, pressing his forehead to theirs making their cries down die again. It didn’t take much to bring them comfort, Frisk running their hand over his face before calming down to sleep again, only whimpering in their pain.

Humans really were vile, disgusting creatures if his shitty attempts at parenting were an upgrade to what conditions Frisk was in prior. 

“What am I doing…?” he whispered to the child who had no way to answer his question but mewled at his pondering anyway, little whimpers hiccupping out of their mouth.

“I don’t know if I can help you, Frisky,” he admitted pulling them close and rocking them a little as he spun his chair lazily from side to side.

“And really, what is a promise?” he stared at the ceiling, closing his eyes, he could practically see stars, real stars. He didn’t need to kill this little one, he didn’t need to break his promise, all he needed to do was give them comfort and let nature take its toll. Be patient a few days, not try to save them, let them go on their own.

That thought made him swallow thickly, he felt just as vile as the humans who just tossed their own into the garbage.

Papyrus wouldn’t know, just like he didn’t know what he had already done….he didn’t know the sins crawling up his back, the sins that had broke their family…

Doing right by Pap was doing the right thing, it was keeping his promises to his friends and it meant not letting innocents die while he did nothing.

He glanced at his phone, he had an hour before Pap got home from school and twenty minutes before she would be at the door, right on time, always on schedule. He groaned seeing he had six missed calls from Undyne, yup, she noticed he hadn’t shown up at his station today. 

Oh how he missed the good old days of Asgore just letting him do whatever he wanted, turning a blind eye on all the sentries.

He nuzzled Frisk once more before putting them back in their basket and tapped their nose playfully to keep those annoyed mewls from turning to screams. He learned a long time ago with Pap a sick baby meant a very loud baby and he didn’t exactly need that kind of attention from any passer byers (who may or may not be his younger over bearing boss). 

Deciding to yank that bandage off, he clicked play on the voice mails before holding it up to his head. Instantly he regretted his life choices but what was new?

“WHERE THE HELL ARE YOU?!”

He rolled his eyes skipping to the next message.

“YOU CAN’T JUST LEAVE YOUR POST!! YOU HAVE THE MOST IMPORTANT POST!! WHAT DOES ASGORE PAY YOU FOR?!”

Next message.

“DON’T THINK I DON’T KNOW YOU ARE IGNORING ME!!!”

Next message.

“LEAVING A DUMMY WITH A POST IT THAT SAYS ‘SANSATIONAL SENTRY WORK’ DOES NOT COUNT AS YOU DOING YOUR JOB!!!”

Sans chuckled, technically he had done his job perfectly, much better then even that dummy who put in more work ethic then him. He bundled Frisk in another blanket as they began to shake again and sighed, he did not expect another baby in his life. He hoped taking all the responsibility for Pap after his mom had left, he wouldn’t have to take on another kid. She would know what to do though and maybe even take the baby from him.

He skipped to the last message.

“YOU THINK YOU CAN HIDE FROM ME SANS??? I TAKE THAT AS A CHALLENGE!!! YOU BETTER BE READY TO FIGHT WHEN I FIND YOU!!!”

He groaned loudly sinking deeper in his chair, lazily scooting around the room, eying the books and notes he had scattered every where trying to find anything on human sickness. He hated it when Undyne’s determination kicked in and she took something as a challenge. It was what got someone her age a position as captain of the royal guards and what got her in Asgore’s good graces to begin with. That side of her was only an asset when you weren’t the challenge.

It wasn’t unusual for Sans to slack on his job, but it was out of the ordinary for him to just disappear for hours and not just be found napping in Grillby’s back room. He didn’t take his job seriously, how could he? It was a massive joke and one not even he could find funny, but it was better then where he once was and he did need it. He needed to give Pap the best of everything, Pap was all he had and working a few dozen sentry stations he didn’t even like to make ends meet was worth it when he could buy Pap that new book or that new doll (all from Sansta, who just had a secretary who didn’t know how to spell his name right). To keep Pap full on all that pasta he loved, get him another sweater cause hey he always needed one more.

He glanced over at the basket the baby was snug in and knew in his heart he couldn’t commit treason and leave Pap alone. He ground his teeth and knocked a stack of paper on the ground, the loud clatter waking the baby and making them moan that awful noise once more. He couldn’t break his promise though and he couldn’t just let them suffer. Humans hurt them too, they threw them away, in Sans book that made them the same.

Their parents had left them alone. Abandoned them. Sans stared off remembering banging on the door, flashing lights going off, screaming for his father to stop…. That dead stare he gave him and the apology he whispered in his ear before walking into the room and closing it off so no one could save him from that the fate he chose for himself…

Sans grit his teeth as the tears began slide down and fog his vision. The bastard took the easy way out leaving a teenager to take care of his toddler brother.

Sans didn’t want to be him, he stopped taking any responsibility that wasn’t his brother after that, but the baby, their parents weren’t any damn different. Sans held no pity for them, he didn’t care why they felt they couldn’t take the responsibility, but Sans wasn’t ducking out and taking the easy way out this time. You don’t throw your children away, you don’t leave them alone just cause you’re afraid…

He checked the time again and took another deep breath, collecting himself. Gently he pulled another blanket over Frisk, covering them up. Just in case he ran into anyone by the ruins. 

He took a short cut back into the house and went up to his room, keeping the basket close to him rocking it gently as he went up the stairs. He stood by his door for a second, fingers idly sitting on the door knob staring down at the rustling blanket. He smiled, task forgotten, watching the blanket rise and fall as little fists hit against it, a sound track of annoyed mewls syncing with each gentle wave. Playfully, Sans lifted the blanket before dropping it back on his charge snickering at the louder mewls. They weren’t pained, they were just annoyed.

A part of Sans hated how attached he was becoming of the baby, but that tends to happen being stuck taking care of something that needed him for several hours. Having to clean something this small in his sink (three times to get the gunk off), having to remember doing this with Pap. He didn’t have anything he could feed them but he had managed to get a little bit of milk spoon fed into them until he could go to her. She would know what to do. The former Queen had to know what to do. She couldn’t just make him care about her cause and then know nothing about humans.

In the vast ocean of things Sans just had to accept and couldn’t change, caring for something he promised to protect was far from the worst thing. 

He entered his room, continuing to bounce the child on his hip to help keep them calm as he ripped a piece of paper out of his journal and took a pen out of the trash tornado as it passed near him. He took in the filth for the first time in years and decided this was no place for an already sick child and teleported them both to the kitchen. 

He made the note simple and short but tried to put in one pun for good measure so Pap knew he was good when he found it. 

From there he went straight to her, knowing she was the only one who could help him. The only one who understood he wasn’t just being selfish, who knew this was the right thing to do. 

He gathered his courage and hoped her promise wasn’t just some fluke as he knocked hard on the door and waited.

**Notes for the Chapter:**

> Hope you guys enjoy...


	3. An Undying Problem P1

Toriel had just gotten done with her usual routine when she heard the pounding coming from down stairs and Sans’ voice, more insistent and demanding then normal. She wondered a moment if it was even him, if someone less friendly had found out she was here. In the short time she had known Sans, she had not known him to be this demanding or impatient.

She stood on the stairwell looking down, nervously fidgeting her hands together.

“Please lady…answer…” she heard Sans call pounding again when she still didn’t answer, “I found a baby!”

That got her attention. 

She hurried to the door and stood there a moment listening to Sans ramble on.

“Come on lady, please open up, they need you.” 

She wasted no more time letting Sans in watching him hurry in and slam the door shut firmly with his own magic.

“Sorry, my boss is trying to find me right now and I don’t want to risk hanging around the ruins…especially with them.”

“Your boss…?” Toriel asked raising her eyebrow and nervously glancing at the door, heart almost stopping imaging Asgore forcing his way into her home.

“Not the king,” he elaborated firmly not stopping his quick pace as he marched up the stairs, not even stopping to ask her if it was ok to enter her home. She would chastise him for his rudeness, but she supposed she would be no less rash with a precious little life in the balance.

“The captain of the royal guards,” he grumbled with annoyance, “She has been trying to sink her hook into me all day.”

He paused at the entrance of the stairwell turning a smug smile her way at her confused stare.

“She’s a fish,” he said grinning wider making Toriel give him a small smile, realizing it was a pun to lighten the mood.

“Though to be fair, its more likely she’ll harpoon me.”

“Oh dear,” Toriel said fidgeting her hands, “You and Papyrus will be alright, won’t you?” 

Sans chuckled putting the basket on her chair and bending in front of it, pulling the rustling blanket up and letting it drop back on the baby squirming beneath making them moan loudly making Toriel’s motherly instincts kick in.

“Not Pap, Undyne loves Pap, but she will have a bone pick to me.” 

He sighed shaking his head as he picked the crying baby up and rocking them.

“It was pretty rattle headed of me, I know but I have been hiding from her and that is something you just don’t do. I should have hid the baby in my lab after I found them and gone back to work, I knew she would show up. She is pissed at me after slacking off four days in a row, she is ready to tear my piece by piece after ditching her new mandatory training, usually this wouldn’t be a big deal, but…”

He stared down at the little one he continued to bounce in his arms.

“They needed me, I couldn’t leave them and I didn’t know if you would be here early.”

Toriel gave him a sympathetic look before holding her arms towards him silently begging to hold the baby. Sans hesitated a second, glancing down at the child before sighing and handing them over to the woman. 

“I found them and they were so sick and little, I couldn’t just leave them like that,” he whispered, Toriel’s eyes widening in panic staring down at the small child and taking even breaths feeling the heat blooming in her arms. It isn’t like Chara she told herself firmly a few times as she paced around the room a moment to calm her nerves before heading into the children’s room to find something for the child noticing with alarm that Sans had left them naked under the blanket.

“They had more cloths, but they were filthy and I just wanted to wash them first, I’ll get them to you tomorrow. I don’t think I can return here tonight, not with Undyne hunting me.”

“It is alright,” Toriel said gently unable to really focus on him, just staring down at the child, they were so tiny. Asriel had been much bigger then this when he was born, this little one was half the size of her forearm. She didn’t know if that was just because human babies were so much smaller then monster children (or at the least boss monster children) or if it was from the sickness that no doubt came from neglect. 

“I can make some of my own, I need a few things I can’t get from these parts though.”

“You want me to run some errands for you?” Sans asked frowning knowing that was impossible right now, not with Undyne around. He didn’t want to chance leading her to the former queen and the child.

“Thank you for offering but I do not think that wise,” she said gently bouncing the child as they became fussy, “I will simply ask a ghost to pick up some fabric for me, he has done a few errands for me in the past. I am particularly fond of buying snails from him but always leaves the option open to get me other things you can’t get around here.”

“Is Asgore the reason you can’t leave?” Sans asked gently and she nodded, not looking up.

“I know its not my place to say but the king isn’t a bad guy,” she refused to look at him instead focusing on the child.

“You are correct, it is not your place to say,” she responded more coldly then she had intended making her friend stiffen in his place.

“Asgore and I have history, I don’t expect you to understand,” she said bouncing the child softly as she dug through the drawers of the children’s room pulling out soft, clean linen and pulling Asriel’s old bassinet she had kept all these years out of the closet before brushing past Sans.

“You’re his ex-wife,” the words hit Toriel like punch to the gut, making her slowly turn her head towards Sans temporarily abandoning the work she was doing.

“I know a little more then you think I do, Queen Toriel.”

“How did you…?”

“The door, it can only be opened by a strong magic user, it was sealed shut after Asgore declared war on humanity for taking away his children … your children. No one could maintain that door except a boss monster like Asgore and the only other one around is you. You care about humans like no one in the underground ever would, only someone who raised a human child would feel that way.”

Toriel laughed bitterly at that, “You are very wise my friend, no wonder the king sought you out to be his judge.”

Sans shrugged at that not saying anything, he walked towards her and stood on his tip toes (much to her amusement) to get a better look at the baby again.

“You can help them, right?”

“I will not let them die,” she swore firmly leading him into the kitchen and setting the supplies on the table before handing the baby back to Sans a moment while she ruffled through the cabinets. 

“I’m pretty shit---”

“Language,” Toriel interrupted firmly shooting a glare his way making him smile.

“I’m pretty stinky when it comes to healing magic, so I couldn’t do much for them. I tried to find something to help in my books but not a lot to go for humans. The notes I had were pretty good about injuries, particularly soul injuries, but not sickness. I would have to go all the way to hotland to get better notes but didn’t want to risk it.”

“I know basic remedies,” Toriel informed him laying out mixing bowls and hurrying to the pantry to collect the herbs she had been collecting, “But I am afraid they are only for simple sicknesses, I do not know what this little one has. My magic can hopefully heal it up though. I will be honest with you, injuries are nothing for me, sickness is something that takes time to heal.”

“Frisk will be ok though?” he asked once almost desperately bouncing the child in his arms.

“Frisk?” Toriel asked amused pausing in what she was doing and turning around to face Sans once more.

“I…ugh…thought it would be a good name for them…” Sans grumbled never feeling as embarrassed in his entire life as he felt with the Queen of his people giving him that look at his name choice. 

“It’s a lovely name, Sans but I am surprised you didn’t go for a font, I figured it was a family tradition.” 

“They are human,” Sans mockingly scoffed, “Gotta give them a humane name and not something for baby bones like ‘Franklin’.”

Toriel giggled turning the stove on and boiling the leaves she had found in the pantry and tossing in an assortment of herbs.

Sans’ forte had always been physics, mainly theory of space and time, never been one for chemistry or herbology. He didn’t really know what Toriel was doing and was too lazy to really ask or pretend to care about the lecture that would follow, so he sank at the table and began sorting through the baby supplies she had on stock. 

“I hope you like a lot of green, Frisky,” Sans chuckled to himself pulling out one green and white striped sweater after the other after the other. These didn’t look like they would fit a baby though, maybe when Frisk got older but they looked too big for now.

Toriel chuckled glancing up from her work to give Sans a look, “Are the clothing not to your liking?”

“I think I better give you a Tutorial on picking different colors.”

“I doubt you would help me pick any fabric Sans blue.”

They both began to laugh loudly making the baby cry out once more, loud, wet tears, little fists grasping Sans’ shirt, making Sans snicker.

“Frisking for better jokes?”

“They are so tiny,” Toriel said stepping away from her work for a moment to rest her hand on the baby’s cheek with her large finger, “How was it you acquired them? I did not realize there was another spot in the underground for children to come through.”

“Someone threw them away,” Sans whispered not looking up at the woman grinding her teeth and taking deep breaths to remain calm, “When you said the kids were just tossed down here, I didn’t think it was so literal.” 

Toriel said nothing to him taking the child back, kissing their nose. She looked disappointed but not surprised, she had seen this story too many times before.

“You need not worry about them Sans,” she said to him with a smile taking them back and holding them close, “I have everything under control, you should return home now before you get yourself in trouble.”

The unspoken ‘or get us found out’ was in the sad expression she held looking down at the child, brushing her finger across their forehead making them mewl in annoyance grabbing it making the queen’s smile glow.

Now Sans had never seen the sun, only read about in books and seen it through pictures, but that smile the former queen held radiated the kind of warmth and happiness and hope he had always assumed standing under the sun felt like. 

“The medicine needs to cool and then I will combine my own magic into it and from there they should improve and get better over the next few days. I know it seems serious Sans, but I have seen serious before and I don’t think this is anything compared to that.”

Sans was taken completely by surprise as the woman yanked him into a bone breaking hugging (not literally but lets say he would be feeling this in his bones in the morning).

“Sans, thank you, thank you for sparing this life despite all the hardship it may have caused you. I am so happy to have broken through to you, every child deserves a chance at life.”

There was a lot of things Sans could have done for this situation. He could have comforted and reassured Toriel or told her about how she wouldn’t be alone and he would help her take care of this one and make sure nothing happened to them. He could have made a pun to help keep the mood light, made any joke really to make her staring at him less awkward.

Instead his mind was on his brother and how he needed him too right now, so he smiled at Toriel and let himself out without even a promise of returning. 

He just didn’t have it in him right now to make anymore promises and he knew just by the look she wore for a brief second before her face dissolved into a bright smile that it he broke her heart not promising to come back.

He couldn’t do that yet, maybe sometime in the future he would but now he had bigger fish to fry (pun fully intended).

**Notes for the Chapter:**

> Cut this one in half to post this weekend. Hopefully next week we will have Pap and undyne show up.


	4. An Undying Problem P2

Upon opening the door, Sans knew he was in trouble. If his thought wouldn't have been elsewhere he probably would have seen the warning signs. The burnt pot thrown out the now broken window, the foot prints running around the house, his poor impaled dummy by the garage.

He wasn't really paying attention to his surroundings or he wouldn't have entered his house and had the pleasure of a spear imbedding into the wall next to him, a spilt hair from striking him.

"WHERE THE HELL HAVE YOU BEEN?!"

Undyne in his house, yelling at him, what a way to end the day. A spear almost ending his existence was more of a way to start up the day, not end it. He gave Undyne his biggest grin, the one that said nothing she said was going to make a difference and he probably wasn't going to listen or attempt to change.

Let her fire him, he challenged in his head (even if he was already praying Undyne didn't sense that challenge).

"Something got your Undies in a pinch there, boss?" Sans asked cheekily cutting past her with a short cut and winking at his younger brother who was frowning at him (arms crossed and teeth grinding, if he had lips they would be pouting) on the couch.

"WHERE HAVE YOU BEEN, SANS?" Pap moaned leaping from the couch and grabbing his arm and dragging him to the table where he forced him to sit down, "UNDYNE HAD TO HELP ME MAKE DINNER!"

Sans didn't put many rules on his brother, he was twelve and always on his best behavior in Sans opinion but using the stove without him around was forbidden. Last time he touched the damn thing he burned his favorite scarf and nearly gave their home to the flames.

"sorry Paps, I was doing something important."

And he was but he wasn't going to say in front of the woman behind him still seething who probably wanted his blood (metaphorical blood).

"WHAT WAS IT? ME AND UNDYNE WERE SO WORRIED WHEN YOU DIDN'T COME HOME!"

"It was important," Sans said simply winking at Undyne who was still seething, not taking her eye off him the entire time.

Pap did not look convinced and kept his eyes firmly on his brother as he set a plate of unidentifiable pasta in front of him and sitting next to him with another plate for himself. Sans shook his head, Pap had been waiting for him to eat.

Sans poked at the food in front of him, he wasn't even sure if it was edible, it was a burnt messed coated with a layer of glitter. It wouldn't kill him, he knew that much but it would hurt in another way, his poor taste buds were going to hate him. He just shoved it in his mouth swallowing whole, oh he should have stopped at Grillby's. He shuddered and felt Undyne's satisfied smirk.

He groaned as she joined them at the table.

Sans glanced nervously between Pap on one side watching him closely and Undyne on the other scooting her chair uncomfortably closer to him with each bite he forced down. It was a mistake coming home, he thought to himself regretting leaving the ruins at all. He could have just waited until morning and snatched Pap before this murderous fish got up and both run to the ruins never to be seen again.

Feeling Undyne's breathing on his cheek as he swallowed the last bite he could stomach, he almost considered doing that anyway.

How bad could life be stuck in the ruins?

He glanced over at Papyrus's large, goofy grin as he forced another bite of the awful food and gave him a forced smile. He wouldn't isolate Pap like that and he wouldn't abandon Pap like that. No, he needed time to think. He needed an excuse for what he was doing, hiding from work wasn't good enough.

Undyne had likely been through every part of the underground by now searching for him, maybe even called…

Sans nearly dropped his fork, pulling his largest smile he excused himself to the restroom, taking a short cut to his room, Undyne yelling after him that he didn't even need to physically use the bathroom.

He sank against his locked bedroom door, he had enforced it with enough magic to even keep the likes of Undyne from kicking it down (well right away anyway, with her determination she would find a way in). He watched the trash tornado pass him by, grinding his teeth together.

Alphys. He had forgotten about Alphys cameras. He ground his teeth harder together. She knew, he knew she knew. Even if they weren't near the ruins yet, he knew she had been pushing for them when he left hot land a few years ago. He had seen her leave her lab a few times directing her assistant on where she wanted the cameras.

He had forgotten. How could he have forgotten?!

He needed to make sure Undyne hadn't gone to her yet. He needed to get to her first. He shut his eyes and cursed his damn luck, why did he make that damned promise, it caused nothing but trouble.

He straightened his shoulders, it wasn't Frisk's fault, it wasn't Toriel's fault, they were worth protecting he reminded himself firmly.

He looked around his room once more, he pulled his phone out of his pocket and made the first move. He texted Alphys for the first time in four years. They hadn't talked since their disagreement on the cameras, Sans not liking the idea of her having that much control on other people's lives but of course the king had thought it was an excellent idea after the rampage the last human went on.

'hey Alph, it's me, Sans.' He wrote simply and placed his phone in his pocket knowing it would be awhile before she got back to him. He knew her too well, she was probably in a nervous sweat staring at her phone, knowing exactly what he wanted.

He then took a short cut directly onto the couch making even Undyne jump at his sudden appearance next to her.

"Sorry about that but that spaghetti ran right through me," he said with a wink to Undyne and a groan from Papyrus.

"I PROMISED UNDYNE WE WOULD PLAY A BOARD GAME WHEN YOU GOT HOME, SO I THINK WE SHOULD PLAY IT!"

Sans gave his best smile, he was a skeleton, so it wasn't hard after all and just kept counting in his head to keep himself from grinding his teeth.

Papyrus excitedly ran over to the entertainment center and yanking open the cabinet, digging through it naming off the games they owned. Sans said nothing letting Undyne provide the commentary on what she thought of all the games and stared down his own reflection in the TV.

It had been one of his greatest accomplishments getting that damn thing to work and even pick up one human broadcast channel (it was a Spanish network and he couldn't understand it but it was better then nothing). He was lazy sure but in these lazy bones was enough determination to pull this off.

He watched Pap set up the board game and yell out the rules all the while in his head he was setting up his own pieces and thinking up a strategy of his own.

He glanced over at Undyne and just shrugged as she pettily stole his favorite game piece, the trombone.

His father was a lot of things but he gave him two things he would need to use to his advantage to keep his footing in this game and not slip up thus destroying his brother.

His intelligence and his powerful magic use. He just needed to out smart Undyne and if he didn't…

He hated it, but she was standing in the way of the people he cared about's lives and futures. Kind Toriel, the baby who did nothing and Papyrus's chance at having a future without any of the misery and regret his brother carried.

It was nearly an hour into a game, really, it was only being played by Papyrus. Undyne and Sans staring each other down, both trying to read the other.

Pap had thought it would be more fun to combine two board games together and had smashed the rules of both games into an unplayable mess only he could really keep up with. Undyne with her endless determination, gave it her all to keep up with the game and even beat them but in the end only Pap could win this game.

Even if the rules weren't nonsense only Pap understood, her eye was locked on him, she wouldn't keep up with Pap's boundless energy distracted like this. Eye constantly scanning over him for any sign of the area of the underground he was hiding in. Sans took relief in this scrutiny, it meant she hadn't gone to Alphys, no she wanted to find out on her own. This was her game to win.

"Don't be rude, see me out," Undyne commanded as she headed towards the door and Sans made no attempt to follow her.

"GO ON SANS! DON'T BE RUDE!"

Sans rose from the spot he had previously been sitting on the floor, leaning lazily against the side of the couch, lightly dozing while his brother and his 'guest' finished up their game. He had been disqualified from the last round for being lazy and not caring enough and had just been ready to take a nap before getting Pap ready for bed when Undyne declared he escort her to the door. He grumbled something about rather seeing his thoughts to dream land but he was ignored, as always.

He took a short cut and landed in front of Undyne leaning casually against the door frame much to both Undyne's and Papyrus's annoyances.

He opened the door and mockingly bowed to his boss as she exited, shoulders stiff and teeth grinding in frustration at his display. She hated it when he didn't take her seriously.

"Don't think I don't know what you were doing," Undyne said suddenly making Sans tense.

"I wasn't going to say anything in front of Paps but I know what you did," she got up in Sans personal space, she jabbed at his chest making his eye twitch a little in annoyance, but he said nothing.

"I know it was illegal," she pressed, Sans was once more than happy to not have a nose with the fish monster's hot breath hitting him in waves.

"Well?" Sans challenged using all his energy to keep that lazy smile hiding his frustration, "Don't leave me in suspense. What was so fishy about my activities?"

Sans saw through her bluff, he wasn't just any sentry who would cower in fear under her, he wasn't just any monster in the underground doing some small and insignificant illegal thing.

Undyne flashed him that smile, that smile that you knew she was using to try to be cool and fill her victim with dread and intimidation. That smile Sans could only guess she got from some awful anime Alphys dug out of the garbage. That predatory smile that would should have sent shivers down her prey's spine.

Sans however was unamused and titled his head and shrugged his shoulders. Undyne's face fell, her one and only tactic hadn't worked, really proving how unprepared for this job she was. Crime just didn't happen in the underground, it was hard to really prefect skills into getting people to confess them if they never happen and people were usually just up front about whatever had occurred.

They both stood, glaring at one another, the wind whistling through the trees and fluttering Undyne's hair, the perfect scene before the perfect battle.

Sans's flashed his goofiest grin effectively ruining the moment and shrugged.

"You got me….what I was doing was pretty bad, even for me."

She kept staring at him demanding he go on as the seconds ticked by and the wind picked up making goosebumps break across her bare arms and her teeth grind against the cold.

"Oh? You want me to say?" he asked feigning shock, "I thought you already knew?"

"I do know," she ground out, "And you aren't going to like the consequences!"

"Which are?"

Undyne's feet began to stomp the ground a little in annoyance and cold, teeth continuing to grind in frustration, her tactic didn't even phase him.

"From this moment on, you are to report to the waterfall sentry station at five am sharp! So-"

"You can keep an 'eye' on me?" Sans asked with a wink which Undyne sneered at before stomping off.

Sans's smug smile turned into a frown as soon as he saw her leave. He knew it was a matter of time before she went to her best friend about this, Undyne would not give up. He needed to get to Alphys first and take that footage from her. Maybe even loop the footage around the ruins from now on.

It was only a matter of time before he was caught and he needed to cover everything up fast.

Sans didn't want to bring his frustration and annoyance inside, so he kept it outside with him hoping the cold air would cool his nerves. He leaned against the shed and just stared down the road where Undyne had vanished.

He hated her right now. That was a sentiment he usually saved for no one, it took too much time and effort and work to hate someone and keep up that level of anger but boy did he feel it right now.

He looked up at the ceiling, the lights were dimmed to indicate how late it was, the closet thing they had to light.

He should give the hate he held at this moment to the baby, he thought, their species was the reason they had to rely on artificial lights to begin with.

He shook that thought away as soon as it arose, Frisk was a baby and he was dealing with Undyne and her nonsense to keep them and Toriel safe. Toriel was his friend and he promised to protect the baby and he was, even if that now seemed to include not seeing either again.

Really, he was ok with that, that was protecting everyone. His brother, his friend and the child he promised to protect.

He raised his head out of these thoughts at the sound of crunching snow.

"Sans?" he smiled towards his younger brother, tilting his head towards the vacant spot by him so he could take a load off next to his big brother.

"What's up bro?" he asked making his smile somehow bigger, just for his brother. He didn't need to put in much energy, Pap was the only thing close to hope he had in his life and that alone was reason to smile about.

Papyrus didn't take the offered seat, just standing in front of his older brother twitching nervously.

"You don't have to hide it anymore, I already know what was going on."

Sans instantly straightened at that, spine painfully popping not used to doing anything but slouching. This could turn bad…

"Hiding what…?" he managed to get out as his teeth ground together, the cogs in his head turning, he needed a lie, he needed one fast.

"I found the baby cloths in the dryer when I got home, you never do laundry, I knew it was something special. A secret, the thing you had to take care of you mentioned in your note, it was a baby."

"Pap, I don't have a baby."

"Well, not yet!" Pap yelled at him making Sans more confused then ever staring at his younger brother, "You have to file the appropriate paper work with the special person you are always making those awful jokes for to the stork!"

He just stared at his younger brother, maybe he should talk to him about some things.

"Pap you don't need to file paper work to get a baby….there is no passion in that. You have to draw your baby."

Papyrus seemed to consider this, placing his hand on his chin making Sans somehow smile brighter. He loved that innocent and determined stare his brother had when he was figuring things out.

"I suppose you would have to be passionate to make a baby even half as great as me," he concluded with a firm nod making Sans laugh wrapping his arm around his brother's neck.

"It would really be grating for me to attempt to make anyone half as great as you, Paps."

"Sans!" he yelled shoving his brother away.

"Face it, you're smiling, bro!"

He laughed following after his brother as he made his way inside.

"I am and I hate it!" he declared rushing up the stairs, his brother not far behind.

Sans flipped his phone open after he noticed Pap had finally fallen asleep (though not for long knowing his brother). He didn't waste time taking a short cut to hot land seeing the response.

'uh hi sans…'

Followed by a more serious message seconds later.

'I know about the human, Sans.'

**Notes for the Chapter:**

> What's this? a cliffhanger? Pray I can keep a schedule so you can find out what happens sooner!


End file.
